1. Field of Invention
The present invention relates to power converters, and more particularly, the present invention relates to a transistor gate driving circuit.
2. Description of Related Art
Recently, power converter designs are used to support high output current that might be greater than 100 Amperes. A key challenge at this power level is to reduce power loss to keep system efficiency as high as possible. The power converters thus provide a gate drive voltage that is a function of the output current. Typically, the gate voltage is in the higher range for heavy-load currents and it is lower range for light-load currents. These voltages give optimal gate drive efficiency for both load conditions. The circuit operation of the gate driving circuit is shown in a prior art of “Adaptive gate drive voltage circuit” by Ahmad, U.S. Pat. No. 7,265,601. However, it requires additional device such as current-sense resistor that causes additional power consumption. In traditional design, the voltage between the gate terminal and the source terminal always keeps at a fixed voltage. The switching loss will be dominated when the output currents are at light-load.